#include <stdio.h>
#include "csapp.h"

int main(int argc, char **argv)
{
	char **pp;
	struct in_addr addr;
	struct hostent *hostp;
	if(argc != 2)
	{	fprintf(stderr,"usage:%s <domain name or dottd-decimal>\n",argv[0]);
		exit(0);
	}

	if(inet_aton(argv[1],&addr) != 0)
		hostp=Gethostbyaddr((const char *)&addr,sizeof(addr),AF_INET);
	else
		hostp=Gethostbyname(argv[1]);
	printf("official hostname:%s\n",hostp -> h_name);

	for(pp=hostp -> h_aliases;*pp!=NULL;pp++)
		printf("alias:%s\n",*pp);

	for(pp=hostp->h_addr_list;*pp!=NULL;pp++)
	{
		addr.s_addr=((struct in_addr *) *pp) -> s_addr;
		printf("address:%s\n",inet_ntoa(addr));
	}

	exit(0);
}
